Outboard drive unit for boats

ABSTRACT

An outboard propulsion drive unit for a boat with an inboard engine utilizes a hydraulic pump on the engine hydraulically connected with a universal swivel mounting which receives an outboard propulsion unit to provide steering about a generally vertical axis and up-tilt motion about a transverse horizontal axis. The swivel mounting has a pair of hydraulic conduits extending through the bearing journals of both axes. The propulsion unit has a hydraulic motor geared to drive the propeller. A reservoir and a charging pump are mounted in the propulsion unit, the latter driven by the hydraulic motor.

United States Patent Jeffery et a1.

[54] OUTBOARD DRIVE UNIT FOR BOATS [72] Inventors: Robert W. Jeffery, Franklin; Robert A. Brown, Jr., Goodrich; Allen F. Cullen, Grosse Pointe Farms, all of Mich.

[73] Assignee: Sperry Rand Corporation, Troy, Mich.

[22] Filed: Aug. 12, 1970 [21] Appl. No.: 63,243

[52] 0.5. CI. ..ll5l35, 115/34 A [51] Int. Cl ..B63h 25/42 [58] Field ofSearch ..115/35,41,34, 34 A,41 HT; 137/580 [56] References Cited UNITED STATES PATENTS 2,766,715 10/1956 Waterval ..l15/34 A 3,587,511 6/1971 Buddrus ..ll5l35X July 4, 1972 FOREIGN PATENTS OR APPLICATIONS 62,963 11/1922 Sweden.... ..ll5/34A 703,154 2/1965 Canada ..ll5/34A Primary Examiner-Milton Buchler Assistant Examiner-Carl A. Rutledge ArtorneyVan Meter and George 57 ABSTRACT An outboard propulsion drive unit for a boat with an inboard engine utilizes a hydraulic pump on the engine hydraulically connected with a universal swivel mounting which receives an outboard propulsion unit to provide steering about a generally vertical axis and up-tilt motion about a transverse horizontal axis. The swivel mounting has a pair of hydraulic conduits extending through the bearing journals of both axes. The propulsion unit has a hydraulic motor geared to drive the propeller. A reservoir and a charging pump are mounted in the propulsion unit, the latter driven by the hydraulic motor.

10 Claims, 7 Drawing Figures INVENTORS RoberzUlJeff Eobenfl. Erownj. 6

ill/e119: en m ATTORN PATENTEDJUL 4 I972 sum 20F 5 INVENTORS KoberzZIZJefi ATI'ORNEY OUTBOARD DRIVE UNIT FOR BOATS Inboard-outboard drive units for boats have heretofore utilized mechanical driving connections between the inboard engine and the outboard propulsion unit. Since the propulsion unit must partake of a universal swiveling motion about a vertical axis to steer and about a transverse horizontal axis for uptilt movements, these mechanical connectionsbecome rather complicated and it is difiicult in the space available to provide mechanical drives of adequate durability. This is particularly true in the higher horsepower ranges, for which inboard-outboard drives are particularly desirable. The mechanical expedients commonly utilized to transmit power from the fixed transom to the movable propulsion unit require either universal joints and telescoping splined shafts or a plurality of pairs of beveled gears, and these must be mounted within protective and lubricant enclosing covers which are difficult to maintain tightly sealed under the complex motions to which they are exposed.

It is an object of the present invention toprovide an improved propulsion drive for a boat with an inboard engine and an outboard propeller which will avoid the foregoing difficulties and will provide efficient operation over a long life with drives of small or large horsepower.

A further object is to provide a propulsion drive of this character wherein the driving connections on the inboard side of the transom permit complete flexibility of choice in the positioning of theengine within the boat hull by eliminating the need for any mechanical connection between the engine and the transom. e

These objects are achieved by the present invention, which consists in a propulsion drive for a boat having a transom, an engine inboard of the transom, and a steerable and tiltable screw propulsion unit outboard of the transom and supporting a screwpropeller which has the improvement comprising a hydraulic pump coupled to be driven by the engine, a hydraulic motor mounted in the propulsion unit and coupled to drive the propeller, a pair of. fluid conduits connected to thepump and passing through the transom, a universal swivel mounting attached to the outboard side of the transom and supporting the propulsion unit, and means forming a pair of conduits extending through the swivel mounting from the first-mentioned conduits to the hydraulic motor.

The invention also consists in a biaxial hydraulic swivel joint comprising a T-shaped pintle member having a pair of bearing surfaces on-the head of the T and a third bearing surface on the stem of the T, a pair of hollow arms having journals embracing the first bearings, a third arm having a journal embracing the third bearing, together with means forming a pair of separated hydraulic conduits extending one from each hollow arm through the pintle, member to the third arm.

The invention furthermore consists in an outboard drive unit fora boat comprising a universal swivel mounting having a pair. of hydraulic conduits attachable to the transom of a boat, a propulsion unit attached to the swivel mounting and having a pair of hydraulic conduits connected with the firstmentioned conduits, a hydraulic motor connected with the last-mentioned conduits, and a propeller mechanically connected to be driven by the hydraulic motor In The Drawings:

FIG. 1 is a fragmentary sectional view of a boat incorporating a preferred form of the present invention.

FIG. 2 is a fragmentary section on line 2-2 of FIG. 1.

FIG. 3 is a longitudinal sectional view of the propulsion unit attached to'the boat of FIG. 1.

FIG. 4 is a rear view of the propulsion unit of FIG. 3.

FIG. 5 is a top view of the propulsion unit of FIG. 3.

FIG. 6 is a view taken on line 6-6 of FIG. 4.

FIG. 7 is a view taken on line 7-7 of FIG. 4.

As illustrated in FIG. 1, the boat has a transom 10 forward of which is mounted an engine 12. The engine may be mounted in any convenient or desirable position in the boat so long as there is roomto mount, upon its output end, a hydraulic pump 14 and to provide a pair of hydraulic conduits 16 leading to the transom 10. If desired, more than one engine l2 and hydraulic pump 14 may be mounted in the boat and connected together with conduits leading to the transom. The pump or pumps 14 may be either of the fixed displacement or the variable displacement type. The fixed displacement type requires installation of a directional control valve for providing forward-reversing operation and neutral, while the variable displacement type provides these functions inherently, along the additional function of varying the speed ratio of the drive to any desired value.

Secured to the outboard side of the transom 10 is a propulsion unit, generally designated 18 and illustrated in more detail in FIGS. 2 through 7. A pair of hollow arms 20 are secured to the transom in alignment with the conduits l6 and have oppositely facing journal bearings 22into which fluid conduits 24 open. The bearings 22 are lined with sealing sleeves 26, which are centrally grooved on their inner and outer surfaces and have a plurality of radial perforations extending through them to allow fluid flow to and from the conduits 24. V

Joumaled in the sealing sleeves 26 and bearings 22 is a T- shaped pintle member 28 which has a depending trunnion journal 30 surrounded by a sealing sleeve 32. Sleeve 32 has two pairs of axiallyspaced inner and outer grooves and two sets of radial holes extending therethrough. The pintle member 28 has a pair of separated fluid passages 34 and 36 which extend from radial passages 38, connecting with conduits 24, to radial passages 40 and 42 in the depending trunnionmember 30. The hollow arms 20 have counterbores 44 which engage with sealed journals on the trunnion-member 28 and serve to collect any seepage fluid from the sealing sleeves 26. Seepage drain passages 46, 48 and 50 lead to the lower end of the trunnion 30. The branch S2collects seepage from the upper end of the sealing sleeves 32.

The trunnion 30 carries ball bearings 54 and 56 which rotatably support the movable portion of the propulsion unit 18. A groove 58 and one or more pins 60 hold the unit in position on the trunnion. In alignment with the radial passages 40 and 42, there are annular grooves 62 and 64 which connect with internal fluid conduits 68 and 70. Due to the radial passages through the sealing sleeves 26 and 32 and to the inner and outer annular grooves thereon, the forces exerted by hydraulic pressure in either of the passages 34 and 36 are balanced inall directions so that there is no interferencewith free oscillatory motion of the pintle unit in the bearings 22 or of the propulsion unit on the trunnion 30.

As shown more particularly in FIG.3, the propulsion unit 18 carries a hydraulic motor 72. This is shown as one of the type having axial cylinder bores in a rotary block which carry pistons reacting against an inclined swash plate, although other types of fixed displacement hydraulic motors could equally well be utilized. The conduit 70 conducts with one of the arcuate distributing ports 74 of the motor 72 and similarly the passage 68 connects with the other distributing port of the motor. The output shaft 76 of the motor 72 extends vertically downward to drive a charging pump 78 and has an extension 80 which drives bevel gearing 82 and 84 for operating the screw propeller 86.

The lower portion of the propulsion unit 18 is formed to provide the fluid reservoir 88 in which the bevel gearing is enclosed and which contains a supply of hydraulic oil utilized for make-up and cooling purposes in the main hydraulic circuit which includes the pump 14 and the motor 72. An inlet or suction pipe 90 leads upwardly from the reservoir 88 to a manifold section 92 and connects by passages 94, 96 and 98 to the inlet 100 of the charging pump 78. The outlet passage 102 of the charging pump 78 connects by passages 104, 106 and 108 with one of the main fluid conduits 68 or 70 and by a branch 110 with the other main conduit. Suitable inlet check valves, not shown, are provided in these conduits. The relief valve, indicated at 112, limits the pressure in the outlet side of the charging pump and can overflow through a passage 114 through a discharge tube 116 leading to the reservoir 88. A seepage drain conduit 118 also connects with the discharge tube 116 from the lower end of the trunnion member 30.

The propulsion unit 18 also includes water intake and exhaust discharge passages which are connected, respectively, by the flexible bellows connections 120 and 122 with the appropriate ports in the transom 10. The water intake passage 124 extends downwardly to intake louvers 126. The exhaust passage 128 extends downwardly and rearwardly to a discharge port 130. Steering arrangements and up-tilt provisions may take any suitable form, such as the hydraulic cylinders (one of which is indicated at 132 in FIG. I).

In operation with the hydraulic system filled with the hydraulic fluid, the drive from the engine passes to the pump 14 which supplies fluid through one of the connections 16 to the appropriate hollow arm 20, whence it passes through the T-shaped pintle member and the appropriate one of the passages 68 or 70 to the motor 72. This drives the propeller 86 through shaft 80 and gearing 82 and 84. It also drives the charging pump 78, which maintains a suitable charging pressure on the other one of the conduits 68 or 70 and through the appropriate check valve in one of the passages 108 or 110 supplies any fluid which may have been lost by leakage during operation. The excess fluid delivered by the charging pump passes over the relief valve 112 back to the reservoir 88 and any seepage which occurs at the journal bearings in the pintle member 28 is collected through the seepage passages previously described and also returned to the reservoir. Control of the drive, in the case of a variable displacement pump 14, is obtained by the usual displacement control mechanism provided with such pumps to cause the drive to be varied at will between neutral and forward or reverse at any speed ratio desired. In the case of a fixed displacement pump 14, forward, neutral and reverse are obtained by operation of the directional control valve associated therewith. Since the drive need not be operated in reverse except for short intervals, it is not essential that the charging pump be operative in reverse, although a pump could be utilized, if desired, which delivers in one direction from either direction of rotation.

We claim:

1. In a propulsion drive for a boat having a transom, an engine inboard of the transom, and a steerable and up-tiltable screw propulsion unit outboard of the transom and supporting a screw propeller, that improvement comprising a hydraulic pump coupled to be driven by the engine, a hydraulic motor mounted in the propulsion unit and coupled to drive the propeller, a pair of fluid conduits connected to the pump and passing through the transom, a universal swivel mounting attached to the outboard side of the transom and supporting the propulsion unit, and means forming a pair of conduits extending through the swivel mounting from the first-mentioned conduits to the hydraulic motor.

2. A drive as defined in claim 1 having a fluid reservoir formed in the propulsion unit and a charging pump coupled to the hydraulic motor and connected to the reservoir and to one of the conduits to maintain the conduits filled during operatron.

3. A drive as defined in claim 1 wherein the hydraulic motor has an output shaft spaced from the steering axis of the swivel mounting and connected by bevel gearing to the propeller.

4. A drive as defined in claim 1 wherein the swivel mounting includes a pair of hollow arms secured to the transom, coaxial bearings in the arms, a T-shaped pintle member mounted in the bearings and having a depending trunnion portion on which the propulsion unit swivels, and a pair of passageways in the pintle member extending from each of the hollow arms to the propulsion unit at points axially based along the trunnion portion.

5. A drive as defined in claim 4 wherein a third passageway in the pintle member forms a seepage drain between the bearings and the propulsion unit.

6. An outboard drive unit for a boat comprising a universal swivel mounting having a pair of stationary hydraulic conduits attachable to and extending through the transom of the boat, a propulsion unit attached to the swivel mounting and having a pair of hydraulic conduits connected with the first mentioned conduits, and including swivel oints pivoting about two axes,

a hydraulic motor connected with the last-mentioned conduits, and a propeller mechanically connected to be driven by the hydraulic motor.

7. A drive unit as defined in claim 6, wherein the propulsion unit includes a charging pump driven by the hydraulic motor.

8. A drive unit as defined in claim 6 wherein the propulsion unit includes a fluid reservoir.

9. A drive unit as defined in claim 8 including means for draining seepage fluid from the swivel mounting.

10. A drive unit as defined in claim 6 wherein the swivel mounting includes hydraulically balanced fluid connections at each swivel axis. 

1. In a propulsion drive for a boat having a transom, an engine inboard of the transom, and a steerable and up-tiltable screw propulsion unit outboard of the transom and supPorting a screw propeller, that improvement comprising a hydraulic pump coupled to be driven by the engine, a hydraulic motor mounted in the propulsion unit and coupled to drive the propeller, a pair of fluid conduits connected to the pump and passing through the transom, a universal swivel mounting attached to the outboard side of the transom and supporting the propulsion unit, and means forming a pair of conduits extending through the swivel mounting from the first-mentioned conduits to the hydraulic motor.
 2. A drive as defined in claim 1 having a fluid reservoir formed in the propulsion unit and a charging pump coupled to the hydraulic motor and connected to the reservoir and to one of the conduits to maintain the conduits filled during operation.
 3. A drive as defined in claim 1 wherein the hydraulic motor has an output shaft spaced from the steering axis of the swivel mounting and connected by bevel gearing to the propeller.
 4. A drive as defined in claim 1 wherein the swivel mounting includes a pair of hollow arms secured to the transom, coaxial bearings in the arms, a T-shaped pintle member mounted in the bearings and having a depending trunnion portion on which the propulsion unit swivels, and a pair of passageways in the pintle member extending from each of the hollow arms to the propulsion unit at points axially based along the trunnion portion.
 5. A drive as defined in claim 4 wherein a third passageway in the pintle member forms a seepage drain between the bearings and the propulsion unit.
 6. An outboard drive unit for a boat comprising a universal swivel mounting having a pair of stationary hydraulic conduits attachable to and extending through the transom of the boat, a propulsion unit attached to the swivel mounting and having a pair of hydraulic conduits connected with the first mentioned conduits, and including swivel joints pivoting about two axes, a hydraulic motor connected with the last-mentioned conduits, and a propeller mechanically connected to be driven by the hydraulic motor.
 7. A drive unit as defined in claim 6, wherein the propulsion unit includes a charging pump driven by the hydraulic motor.
 8. A drive unit as defined in claim 6 wherein the propulsion unit includes a fluid reservoir.
 9. A drive unit as defined in claim 8 including means for draining seepage fluid from the swivel mounting.
 10. A drive unit as defined in claim 6 wherein the swivel mounting includes hydraulically balanced fluid connections at each swivel axis. 